KLP-7 restricts neurite growth in TRNs. (A) Confocal images of ALM and PLM neurons expressing Pmec-7::GFP (muIs32) in WT, in klp-7(tm2143), and in WT background expressing Pmec-4::klp-7b (shrEx93). Yellow arrowheads and white arrows indicate the position of the nerve ring and synaptic branch, respectively. In klp-7(tm2143), the posterior process of the ALM shows ectopic growth (orange arrow), while the PLM posterior process is extended moderately (double-sided arrow). In the Pmec-4::klp-7b[+] background, often the anterior process of the PLM is terminated prematurely (red arrowhead). (B) Quantification of ectopic extension in the ALM in klp-7 mutants. N = 4–6 independent replicates; n (number of neurons) = 80–194. (C and D) Confocal images and illustration of the Pmec-7::GFP::RAB-3 (jsIs821) and Pmec-4-mCherry (tbIs222) reporters in the WT and klp-7(0) backgrounds. Yellow arrow indicates the ectopic process in ALM. The green arrowheads indicate GFP::RAB-3 punctae along the processes of PLM and ALM neurons. The white arrowheads indicate the GFP::RAB-3 enrichment at the synaptic region of PLM. (E and F) The normalized length of PLM posterior and anterior processes due to either loss or overexpression of klp-7. Normalized length = (actual length/distance between cell body and vulva for anterior process or distance between cell body to tail tip for posterior process). N = 3–6 independent replicates; n (number of neurons) = 15–55. (G) Confocal image of TRNs (arrows) in worms expressing Pklp-7-KLP-7::GFP (ddIs145) in Pmec-4-mScarlet (shrEx143) background. For B, ***, P < 0.001; Fisher’s exact test. For E and F, ***, P < 0.001; ANOVA with Tukey’s multiple comparison test. Error bars represent SEM.